Also, from Batman on the forums:"The Phantom sub will be completely visible on the world map when actively guarding a base (set explicitly as a guard on your own or an alliance member's base) or when in close proximity to your own base. It will also be visible when engaged in any battle."

Thanks, was wondering if that may be the case after I posted it. Wish the values were really the values instead of div 2 here, div by 5 there, hop on one leg and spin around .... oh wait, that is something different :)